#include<iostream>
#include<vector>
using namespace std;

class Solution {
public:
    int search(vector<int>& nums, int target)
    {
        int left = 0, right = nums.size() - 1;
        while (left <= right)
        {
            int mid = (right - left) / 2 + left;
            if (nums[mid] == target)
                return mid;
            else if (target > nums[mid])
                left = mid + 1;
            else if (target < nums[mid])
                right = mid - 1;
        }
        return -1;
    }
};